Commander Jim Raynor contacted the protoss, but Selendis was sure that Haven had to be purified, and offered the commander the chance to purify the planet himself. DoctorAriel Hanson was able to convince Raynor that she could develop a cure to the virus, making him oppose the protoss and protect the colonists.[3]

The protoss deployed a Purifiermothership to destroy the colony bases. The Raiders brought in Vikings but could not directly engage the purifier; the terrans did not have the weapons to penetrate the shield. However, the shield was generated by three nexus that were vulnerable to attack. Furthermore, the colonists evacuating from the outlying bases were attacked by protoss terror fleets.

The purifier was destroyed after the shield was disabled. The protoss were forced to retreat.

Selendis commended Raynor on his victory, and hoped his belief in the colonists would be vindicated.[3]

After the battle, Hanson left the Raiders to settle with the other colonists. Before leaving, Hanson asked Raynor if he would want to stay with her on Haven and "start over." Raynor declined, unwilling to give up the revolution. Hanson sealed her goodbye by kissing Raynor on the cheek and saying, "You're a good man, Jim Raynor."[4]

The main objective is to destroy the Purifier mothership. Its shields are invulnerable and may only be damaged after the three nexus are destroyed. The Purifier attacks the four outlying settlements before moving on to the fifth, beside which the Raiders have set up their base. After destroying the first settlement the Purifier sends small forces of carriers, void rays and scouts to attack the next targeted settlement and destroy their evacuation ship. Destroying the fliers and saving the colonists yields collectable resource palettes. The starting base is not attacked often. A few bunkers with siege tanks and missile turrets are sufficient for defense.

All the protoss bases use warp prisms to power their structures, and are vulnerable to the new unit for the mission - the Viking. Use two starports with reactors to build Vikings quickly, and possibly expand to the first protoss base for their resources. Goliaths are also useful for this mission, especially with multi-lock weapons systems, due to their high damage vs. air units, and massed can easily take down the Purifier.

The first and second bases may be attacked safely from ledges. Clear away enemy air units to restrict enemy vision. The second base may also have a colossus. The southern and last nexus is protected by carriers and archons, and on higher difficulties high templar. Use Vikings to draw the defenders out, then take out the warp prisms and land to destroy the final nexus. With all three nexuses destroyed the Purifer is rendered vulnerable.

The Purifier may use Vortex on unit concentrations, and warp-in reinforcements. Attack the Purifier with Vikings by following in its wake; this makes it easier to keep the Vikings out of range. Another strategy is to wait until the Purifier is powering up the purifying beam on the last base, and then hit it with eight or more vikings. The Purifier can not attack while it is charging, it is an easy kill. This also prevents the Purifier from attacking your base. In addition, if the Purifier is attacked from behind while it is moving it will not attack the Vikings and not teleport in reinforcements.

Spectres may be used to nuke the last nexus, and inflict significant damage on the Purifier with Psionic Lash. Spectres are less effective on Brutal difficulty as the Purifier becomes a detector.